Install CSF Firewall on Rocky Linux 9 - Full Guide

In this guide, we want to teach you How To Install and Configure ConfigServer Firewall (CSF) on Rocky Linux 9.

ConfigServer Firewall, also known as CSF, is a firewall configuration script created to provide better security for your server while giving you an advanced, easy-to-use interface for managing firewall settings. CSF configures your server’s firewall to lock down public access to services and only allows certain connections, such as logging in to FTP, checking email, or loading websites.

ConfigServer Firewall also comes with a service called Login Failure Daemon, or LFD. LFD watches your user activity for excessive login failures which are commonly seen during brute-force attacks.

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Install and Configure ConfigServer Firewall (CSF) on Rocky Linux 9

Install and Configure ConfigServer Firewall (CSF) on Rocky Linux 9

To complete this guide, you must log in to your server as a non-root user with sudo privileges. To do this, you can follow our guide on Initial Server Setup with Rocky Linux 9.

Install CSF on Rocky Linux 9

First, you need to update your local package index with the command below:

sudo dnf update -y

Then, you need to install some dependencies on your Rocky Linux 9 with the following command:

sudo dnf install wget vim perl -y

Next, switch to your src directory:

cd /usr/src

Download CSF Installer Script

At this point, use the wget command to download the CSF installer script on Rocky Linux 9:

sudo wget https://download.configserver.com/csf.tgz

Extract your downloaded file:

sudo tar xzf csf.tgz

Move to your CSF directory:

cd csf

Run CSF Installer Script

Finally, run the CSF installer script with the following command:

sudo sh install.sh

When your installation is completed, test that you have required iptables modules:

sudo perl /usr/local/csf/bin/csftest.pl

In your output you will see:

Output
Testing ip_tables/iptable_filter...OK
Testing ipt_LOG...OK
Testing ipt_multiport/xt_multiport...OK
Testing ipt_REJECT...OK
Testing ipt_state/xt_state...OK
Testing ipt_limit/xt_limit...OK
Testing ipt_recent...OK
Testing xt_connlimit...OK
Testing ipt_owner/xt_owner...OK
Testing iptable_nat/ipt_REDIRECT...OK
Testing iptable_nat/ipt_DNAT...OK

RESULT: csf should function on this server

Configure ConfigServer Firewall (CSF) on Rocky Linux 9

At this point, that you have CSF installed on your server, you need to edit the CSF configuration file.

Open the file with your favorite text editor, here we use vi:

sudo vi /etc/csf/csf.conf

Find the Testing line and change its value to 0.

TESTING = "0"

When you are done, save and close the file.

Manage CSF and LFD

Now use the following commands to start and enable the CSF and LFD on Rocky Linux 9:

#sudo systemctl restart csf && sudo systemctl restart lfd
#sudo systemctl enable csf && sudo systemctl enable lfd

Verify that your CSF and LFD are active and running on your server with the commands below:

sudo systemctl status csf && sudo systemctl status lfd

Output
● csf.service - ConfigServer Firewall & Security - csf
     Loaded: loaded (/usr/lib/systemd/system/csf.service; enabled; vendor preset: disabled)
     Active: active (exited) since Thu 2022-09-22 09:26:14 EDT; 31s ago
   Main PID: 11375 (code=exited, status=0/SUCCESS)
        CPU: 505ms
...

Output
● lfd.service - ConfigServer Firewall & Security - lfd
     Loaded: loaded (/usr/lib/systemd/system/lfd.service; enabled; vendor preset: disabled)
     Active: active (running) since Thu 2022-09-22 09:26:23 EDT; 39s ago
   Main PID: 11421 (lfd - sleeping)
      Tasks: 1 (limit: 23609)
     Memory: 138.9M
        CPU: 4.233s
     CGroup: /system.slice/lfd.service
...

You can check your CSF firewall version on Rocky Linux 9 with the command below: